From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0313E2C027B for ; Mon, 25 Aug 2025 09:26:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756113984; cv=none; b=MGheEwc7MuijfsSFKUKnMtoUqA/SYDLy3t/X3wxAbvtAOnklnJgb4yMaHK8m44bAq5gZ/JMCTNxz9aEbv1MOOtNfxoRuBKZtUXSrEGHkdd7M+O+Vq3OR0OaILHS2mUTOh03FLQrE0KoktrYG85PJ7WfxZwka3l/X7I8i7oK3E1Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756113984; c=relaxed/simple; bh=cIzdmcvXdg7hxkkZDexpcsEff8DWNSt3EqI8LIw59v8=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=kP34SVJYhJrtTC1wdB8bB7sk8O1DxDk4rOGZWBwVtVnEBe61o+LTi9ZYf093NMgrfRDMmwH99fMq/k+yx1LWh7e02wXAtKlXiMRIEJOVevo3mp707zm99nCo84wFQxl+0CZUP0Jy0k6efJnJFr2IHPh3wzAJCrA/jKhqdCxQosA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=WO2ZIclx; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="WO2ZIclx" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756113979; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=58sTOuEGPWt/oh3phiU0Ohm2TNJomRF2T7ceM8gERPs=; b=WO2ZIclx7JFGeE5p1QwUWOJ3PJqYWGrDGP/ps7Pne7L31r0CAEeUQwfoNeFUe/0CpKWAKl V6ysu4jbPdN6O296+wqa6QC5eSm+7gJtMwHCmgx7W8jcYuvJ2fOuAy1dTy9BP3goj/Nnqw dnsE1U5NAqAlE40nZMiSyEwKZsdVKWE= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-682-OVttxm5WMLqfO-Nw3GtKtw-1; Mon, 25 Aug 2025 05:26:17 -0400 X-MC-Unique: OVttxm5WMLqfO-Nw3GtKtw-1 X-Mimecast-MFC-AGG-ID: OVttxm5WMLqfO-Nw3GtKtw_1756113976 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 04627180028D; Mon, 25 Aug 2025 09:26:16 +0000 (UTC) Received: from localhost (unknown [10.43.135.229]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A0B5E1800447; Mon, 25 Aug 2025 09:26:14 +0000 (UTC) Date: Mon, 25 Aug 2025 11:26:12 +0200 From: Miroslav Lichvar To: Thomas Gleixner , Thomas =?iso-8859-1?Q?Wei=DFschuh?= Cc: linux-kernel@vger.kernel.org, john.stultz@linaro.org Subject: CLOCK_AUX stepping Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 There is an issue with the new system auxiliary clocks. When I make a larger step of a CLOCK_AUX clock (by clock_settime() or adjtimex(ADJ_SETOFFSET)), the system slows down significantly to almost being unusable. This didn't happen with the original tglx/timers/ptp/driver-auxclock branch, but happens with 6.17-rc1 and later. Reproducer: - echo 1 > /sys/kernel/time/aux_clocks/0/aux_clock_enable - git clone -b staging https://github.com/mlichvar/linuxptp.git - cd linuxptp && make - ./phc_ctl CLOCK_AUX0 set "echo 0 > .../aux_clock_enable" revives the system. I'm not sure if this isn't just a symptom, but the top functions reported by perf are: 87.10% swapper [kernel.kallsyms] [k] queued_spin_lock_slowpath 6.84% rcu_exp_gp_kthr [kernel.kallsyms] [k] queued_spin_lock_slowpath 1.90% rcu_exp_gp_kthr [kernel.kallsyms] [k] smp_call_function_single -- Miroslav Lichvar